The Origin of a Rainbow
by Dianchi
Summary: Everypony knows about the pot of gold at the end of a rainbow. But few ever go searching for the beginning. In which a series of events collide to reveal the mystery of Rainbow Dash's father. Well written crackfic.
1. Take One Hint and Add Half of Another

The first clue was the humming. No matter where they went, Rainbow Dash could be caught lightly humming some determined tune under her breath, occasionally even twitching her neck up and down as if bobbing to some beat only she could hear. Applejack was, of course, the first to call her out on it. She could didn't mind humming on principal – heck, she liked to belt out a few lines of "Don't Wait for Daisy" when she was out bucking by herself in the far Fuji pasture – but three solid weeks of the same song was enough to drive anypony crazy.

"Dash, it sounds like a mighty fine song, but could ya' please reign in the hummin'? Yer drivin' me crazier than Fluttershy's vegetarian ferrets listenin' to a lecture from Derpy Doo." Applejack ground out one afternoon as they gathered around a table for lunch.

"Oooh, Dash's humming a song? I love songs! They go well with parties! And we're having a party! You should sing it aloud so we can all hear it!" Pinkie Pie squealed, completely oblivious to the way Rainbow's coat had suddenly become three shades lighter and the tight, defensive way she was holding her wings.

"Pinkie Pie, this isn't really a party. Just a little luncheon I invited you all to so that we may celebrate Twilight's continued success." Rarity clarified with a little nod of her horn towards a blushing Twilight. "Thirty-five spells is really quite a feat, my dear, and one most certainly worth celebrating."

"All the more reason to have a song for it!" Pinkie Pie announced. It really was a statement about the citizens of Ponyville that no one else in the restaurant even looked up at this.

"I don't know." Rainbow said uneasily. "It doesn't even really go with something like this and I don't wanna take away from Twilight. Applejack's right, I'll just knock it off."

"Awwww!" Pinkie Pie practically melted to the floor in disappointment. "Maybe it's actually the perfect song for today! You never know unless you tell us and we decide! Tell us! Tell us! Tell us!"

"Uhhh…"Rainbow shuffled back a few paces in response to Pinkie's pressing chant. "It's about harmony, I guess. Living together in harmony forever." If at all possible, she clenched her wings even tighter.

"Really?" An enormous grin spread over Pinkie Pie's face. "I know that song! It's perfect!" She bellowed. "I don't why I didn't think of it before!"

"Uh, Pinkie—" Twilight tried to cut her off but it was too late. She was off, a magnificent pink blur belting out:

_In harmony__  
><em>_Harmony__  
><em>_You're you, I'm me__  
><em>_Together we__  
><em>_Can live in harmony_

In the resulting confusion (_If there was only one note/__How boring life would be!_) no one noticed how Rainbow quietly let a sigh of relief escape her mouth.

* * *

><p>The next clue was a little more obvious. Cheerilee had just started the very large and complicated unit on magic in Equestria, explaining how very important magic was in everypony's life. And to make things even more special, the teacher for Scootaloo and Sweetie Bell's class had come down with a cold, forcing Cheerilee to combine the two classes today. It was no wonder the lesson took a turn for the crazy.<p>

"Okay class, settle down please." Eighteen young ponies, crammed into a room meant for nine, stilled in their fidgeting and talking, at least for next ten minutes. Cheerilee breathed a sigh of thanks and smiled at them all. "Thank you. Now today we are going to continue our discussion on how everypony in Equestria uses magic. Did you all ask your friends and family how they use magic? Yes Sweetie Bell?"

"Rarity uses her magic to move all the things needed to make one of her dresses." She said.

"That's right, as a unicorn, Rarity uses magic in a very visible way. How about other types of ponies? Yes Applebloom?"

"Applejack says Earth Pony magic is what gives her and Big Macintosh their strength to do all that applebuckin'." She announced proudly, nudging her nose slightly higher in defiance once the whispers and snickers about poor farmer ponies reached her ears.

"You are absolutely correct, Applebloom." Cheerilee said. She narrowed in on the two snickering fillies on either side of poor Applebloom and summoned up her best teacher voice. "Diamond Tiara, Silver Spoon, do either of you have something you'd like to add?"

Unsurprisingly, it was Diamond Tiara who responded.

"My mother told me that a pony's coat color was magic. Otherwise everypony's coat would be just like parents' and somepony's herd would be stuck with all the yucky colors. And it's why my coat is so perfectly magenta, unlike any one else in my herd." It was at that moment Cheerilee started to silently panic while her class broke out in noisy confusion.

"What?"

"Really? Is that why my mommy's coat is pink and I'm green?"

"Naw, that's impossible. My dad's coat is blue and that's why I'm blue."

"Cheerilee, is that true?" Several plaintive voices rang out at once as everyone began twisting around in their seat to suddenly examine their coat and compare it against the other coats and manes found in town.

"Now if everypony can please calm down." Cheerilee cooed sweetly. She cooed with a little extra sweetness at Diamond Tiara."Now it is true that a pony's colors are not necessarily going to be the same as his or her parents' colors, especially when it comes to colors of his or her mane. But nopony knows for sure what causes each pony to be born with certain colors, but I have heard that the leading theory is a combination of magic and genetics. So Diamond Tiara is partially correct." Cheerilee finished with a quick look at each of her young pupils. They appeared to be stunned into a welcomed silence. Then Archer slowly raised a hoof.

"Yes Archer?"

"What are genetics?"

"Oh, I know!" Twist squeaked excitedly as Cheerilee's heart plummeted even further than before. "It's the stuff everypony has inside them makes up everything about them! Then you mix your stuff together with another pony's stuff so the filly or colt gets a little bit of both parents."

"You mean like blood?" Diamond Tiara demanded in a horrified voice as Cheerilee struggled not to faint at Twist's fantastic description of "mixing stuff together." "I thought it was just reason why everypony in my herd has perfectly violet colored hair. Not something completely gross like blood."

"Blood's not gross, it's natural!" shouted Tornado Bolt, who was seated on the farthest away from Diamond's glare and felt safe enough to defend science. The entire class seemed to swell and was poised on bursting out into another loud argument when Coronet's question rose above the general hubbub.

"What do you mean, somepony's herd would be stuck with the yucky colors? What colors are yucky?" Diamond Tiara actually seemed to blush at this.

"Well, you know, stuff like yellow and brown and gray. Boring colors."

"Hey, my coat is yellow. That's not nice!" Sunny Daze protested.

"Doctor Whooves has a brown coat _and_ a brown mane. There's no way he's boring." Archer said.

"Silver Spoon is gray." Twist pointed out. "Maybe you need your eyes checked out. My doctor's really good, I can get you an appointment with her if you want."

All Cheerilee could think as she rallied the class back to order and attention, was thank Celestia that this time no pony had thought to ask how genetics are mixed.


	2. Half that Hint Left to Stew

All Scootaloo could think about was how genetics are mixed. Despite what Cheeilee had said, Scootaloo didn't really believe magic played that big of a role in determining everypony's colors. After all, her mother had a bright orange mane that showed itself well as Scootaloo's coat and she shared her dad's strong fuchsia mane and violet eyes. Sure, a pony might be born with stripes in his or her mane, like Twilight's slivers of purple and pink, that no other pony in the herd would have. But that was just stripes. You could grow out of stripes.

"And then Applejack told me that 'cause everythin' had settled down and the Buffalo Tribe are back to their normal stampedin' grounds, I could go with her the next time she goes to Appleloosa. Isn't that awesome?" Applebloom said to Sweetie Bell as they came up on Scootaloo's left flank.

"Absolutely!" Sweetie Bell nodded enthusiastically. "Rarity always says I'm too little to go with her on any of her buying trips, but I hoping maybe next time she'll let me go with her to Fillydelphia."

"She has ta!" Applebloom said. "Even Ah've been ta Fillydelphia. It's only half ah day's walk."

"That's what I said!" Sweetie Bell agreed. There was a pause as they both glanced right, waiting for Scootaloo's input. But the little filly continued to tread along silently (occasionally pausing to scratch some weird sort of square in the dirt). For all intents and purposes, she appeared to be ignoring them. Sweetie Bell and Applebloom exchanged a look.

"Get her!"

"So then you divide by the largest number and subtract however many – wah! Applebloom, let go of my tail! Sweetie Bell get off of my wings!" Scootaloo yelled in vain. She thrashed from side to side in an effort to shake them off and was rewarded with short breath and the supporting base role in a pyramid of panting fillies. "What's gotten into you two?"

"You're acting funny. Like your head is stuck up in the clouds and all you can hear is the rushing of the wind." Sweetie Bell explained as she carefully clambered off.

"We thought it would be a good idea ta, yah know, bring yah back to ground somehow." Applebloom said a tad sheepishly. They shuffled over to the side of the path back to Ponyville and plopped down in the shade of a handy maple tree to talk things over.

"So watcha thinkin' about?"

"Rainbow Dash's-"

"Of course." Sweetie Bell and Applebloom chorused.

"-hair and what Diamond Tiara was saying about magic." She finished with a pointed glare. "Dash is the only pony I know of with a mane like that and I don't think she got it through magic."

"How do you mean?" asked Sweetie Bell. She noted the way that they were clustered together under the tree and their low voices had all of the marks of Cutie Mark Conspirators. Maybe they should try being masterminds sometimes.

"Well." Scootaloo drawled out almost reluctantly. "I've seen a picture of her mom. They have the same blue coat. But her mom has a white mane."

"Oh, I know! I think her name is Cloud something. Dancer? Diver? I forgot." Sweetie Bell offered. "But I remember she lives in Cloudsdale and does something for the clouds."

"Exactly. If her mom has a white mane then her mane must come from…" Scootaloo trailed off expectantly.

"Her father?" Applebloom said, a touch confused at the complicated turn this conversation had taken. Scootaloo was acting like they were talking about some great big hush-hush secret.

"Exactly!" Scootaloo cried. "But that what they want you to think!"

"Who's they?"

"I don't know. Your sisters? Twilight Sparkle working for the Princess? Fluttershy's rabbit? It could be anypony! They don't want us to put three and seven together and come out with ten. They don't want us to realize that Rainbow Dash doesn't have any father." Scootaloo beat her wings unconsciously, raising herself over her friends and loudly proclaiming this conclusion to the (thankfully) empty road.

"Really?"

"What? Scootaloo, that's crazy talk." Scootaloo darted back to the ground and began to pace in circles.

"Think about it. Rainbow Dash lives in that amazing cloud house, away from everypony. And she has a running rainbow, which are pretty hard to come by, let me tell you. But all a rainbow really is is water at the right way to get colors, so she has white hair from her mom and she just dunks it in her rainbow and-"

"Scootaloo, I don't think-"

"Rainbow Dash dyes her hair!" Scootaloo yowled horrifically. "It's impossible. Beyond all possible thought. Someone as awesome as Rainbow has to deal with something as stupid and prissy like dyeing her hair!"

"Scootaloo, do ya really-"

"What's wrong with dyeing your mane?" Sweetie Bell's soft voice took on a hard edge. "Rarity dyes things all the time."

"Now thar's nuthin' wrong with dyein'," Appleblossom quickly offered. She had seen what happened when you started on conversations like this. Usually there was quite a bit of polite yelling and escalated shouting before the inevitable angry conclusion. "It's just kinda weird to dye yer mane, that's all Scootaloo is sayin'."

There was a tense silence as Scootaloo and Sweetie Bell breathed deeply and glared at each other, Applebloom darting glances at the both of them.

"Besides, it is impossible to get such a clear dye from a rainbow river." Sweetie Bell pointed out. She fell back onto some technical points, about how all the colors would blend together if someone were to just stick their mane into the river and really the only way to get the flow rate proper would be to do a set filtration that separates each color based on tint and then stabilizes that batch in a non-mobile container. "And even then, she would have to be wearing crystals in her hair at all times make sure the dye reflects the sunlight properly." She finished with a firm nod and looked expectantly at her two best friends.

"Refracta' coversion of whut?" Applebloom managed to muddle out. She swayed side to side under the torrent of information Sweetie Bell had just unleashed and reminded herself to tell Applejack that dress making was just as complicated as growing.

"Well, why couldn't Rainbow Dash just wear those crystals?" Scootaloo said. Sweetie Bell shook her head.

"She would either have to grind them up and dust them throughout her mane or wear a big one at the top of her head. And even, you would have to be at certain angle at a certain part of the day for the effect to work."

Suddenly Scootaloo burst out laughing. "Ground up crystals, really? Like her hair would be all sparkly like those vamponies from those books Twilight hates?" Sweetie also started to giggle.

"Yes! Only, it would be even worse. She would have to be nine thousand times more sparkly."

Scootaloo collapsed on the ground, howling with laughter.

"How big ah crystal are yah talkin' 'bout?" Applebloom asked, relieved they weren't arguing anymore.

"Huge!" Sweetie Bell squeaked. She threw her front hooves as far out as they would go and stretched them out a little further. "Bigger than this _and_ it would have had to have been cut exactly right on all sides."

"Oh wow." Scootaloo gasped out as she redoubled her laughter at the sight. "There's no way she would be able to fly." The laughter started again.

It was some time later that they settled down to manageable giggling and continued on their journey back home. Of course, it was on that journey that Applebloom suggested they just go to Rainbow Dash and ask her to get detective pony cutie marks which lead to an adventure through Ponyville that probably resulted in more detecting than most of the citizens could have ever feared for. But eventually they ended up at Rainbow's house, where she sat stewing over the backlog of some weather reports.

"My mane?" She blinked down at them all in surprise. "My mom has the same blue coat but my dad has a rainbow mane and tail. So from him, I guess."

Sweetie Bell and Applebloom cheered and high hoofed each other. Scootaloo sighed in a mixture of relief that her hero was not in fact stooping to such a demeaning frilly adventure and disappointment that she wouldn't be earning a private detector cutie mark after all.

"From your dad?" Scootaloo repeated, perking right back up. "Just like me!"

"Yeah, kid. Maybe you're a little bit as awesome as me already!" Rainbow grinned as she reached out to ruffle Scootaloo's hair and playfully chase after all the Cutie Mark Crusaders.

* * *

><p><strong>AN: Any theories as to what I'm driving at? I'm curious what people are thinking as they read this. <strong>


End file.
